SpaceX conducts Falcon 9 test; AMOS-6 investigation narrows

As SpaceX narrows on a second stage COPV (Composite Overwrapped Pressure Vessel) as the cause of the AMOS-6 static fire pad failure on 1 September, the company is pressing ahead with hot fire operations on a new first stages at its McGregor, Texas, facility. The new booster is set to power what SpaceX hopes will be a December mission from the soon-to-be-christened LC-39A at the Kennedy Space Center in Florida.

Currently, a Falcon 9 first stage is understood to be patiently waiting at Vandenberg Air Force Base in California. It is believed this Falcon 9 will launch the first mission since the AMOS-6 incident on a December launch that may involve the Iridium NEXT flight.

Meanwhile, a new first stage was spotted at McGregor, erected on the test stand. A hot fire of the nine core stage Merlin 1D engines was conducted on Tuesday, although SpaceX is yet to confirm the event.

It is possible – although not confirmed – this booster will be involved with the first launch from SpaceX’s Pad 39A at the Kennedy Space Center (KSC).

A placeholder date of December 17 was cited on planning Cape documentation over a week ago. The mission was cited as for Echostar-23, although – as expected – SpaceX is yet to provide specifics to its upcoming manifest until after the AMOS-6 investigation has concluded.

Also at McGregor, though currently in storage, is another first stage. It is possible this stage may be used for the CRS-10 Dragon launch, also from 39A.

At present, it is understood that Pad-39A’s final conversion is the primary driving factor toward Echostar-23’s launch, aside from official wrap-up and clearance of the AMOS-6 investigation.

According to a company statement on 28 October, “The Accident Investigation Team continues to make progress in examining the anomaly on September 1 that led to the loss of a Falcon 9 and its payload at Launch Complex 40 (LC-40), Cape Canaveral Air Force Station, Florida.

“Since the incident, investigators from SpaceX, the FAA, NASA, the US Air Force and industry experts have been working methodically through an extensive fault tree to investigate all plausible causes. As part of this, we have conducted tests at our facility in McGregor, Texas, attempting to replicate as closely as possible the conditions that may have led to the mishap.”

What is now confirmed is that the investigation teams have made “significant progress” in eliminating and narrowing elements of the fault tree – with the team now focused on a breach of the cryogenic helium system on the second stage liquid oxygen (LOX) tank.

A COPV is a lightweight tank that consists of a thin, non-structural liner (that acts as a barrier between the fluid inside the tank and the composite to prevent leaks) that’s wrapped with a structural fiber composite.

New procedures were subsequently implemented throughout the Shuttle program to mitigate the risk of a COPV burst failure – which was identified as a possible COPV failure mechanism without a precipitating leak of the vessel.

The two high-risk COPVs on Atlantis were eventually replaced, and Discovery and Endeavour flew out their COPV sets through an overall end of program risk of a 1 in 489 chance of a COPV failure resulting in a Loss Of Vehicle (LOV) or Loss Of Crew and Vehicle (LOCV) event.

Importantly for SpaceX, “Through extensive testing in Texas, SpaceX has shown that it can re-create a COPV failure entirely through helium loading conditions. These conditions are mainly affected by the temperature and pressure of the helium being loaded.”

Recreation of the failure was deemed essential for SpaceX in determining the root cause of the AMOS-6 failure – an element that was complicated by a lack of data due to the short timeline of the failure event at only 93 milliseconds from first signs of an anomaly to loss of data.

With the failure now replicated, “SpaceX’s efforts are now focused on two areas – finding the exact root cause, and developing improved helium loading conditions that allow SpaceX to reliably load Falcon 9.”

As always, the final results of the investigation and the exact improvement plan for helium loading will drive the eventual RTF launch for SpaceX.

However, even if SpaceX is not ready for RTF until January 2017, both of the company’s pads at Vandenberg and the Kennedy Space Center are expected to be ready to support what will be a busy salvo of missions as the company catches up on its manifest obligations.